ks3/lib/common/event.js

本代码库为`金山云存储KS3`服务.主要提供`KS3 nodejs SDK`和`命令行工具`.

function createEventDispatcer (client) {

    var eventObject = {}
    var callbackId = 0

    client.on = function (eventName, callback) {
        if (!eventObject[eventName]) {
            eventObject[eventName] = {}
        }

        const id = '' + callbackId++
        eventObject[eventName][id] = callback
        return id
    }
    
    client.once = function (eventName, callback) {
        if (!eventObject[eventName]) {
            eventObject[eventName] = {}
        }
        const id = 'once_' + callbackId++
        eventObject[eventName][id] = callback
        return id
    }
    
    client.emit = function (eventName, ...args) {
        const callbackList = eventObject[eventName]
        for (let id in callbackList) {
            callbackList[id](...args)
            // 如果是订阅一次的 则需要删除
            if(id.indexOf('once') > -1) {
                delete callbackList[id]
            }
        }
    }

    client.off = function (eventName, id) {
        delete eventObject[eventName][id]

        // 如果是当前eventName里面的最后一个订阅者 则需要将eventName删除
        if (!Object.keys(eventObject[eventName]).length) {
            delete eventObject[eventName]
        }
    }

}

var EventDispatcer = function () {
    createEventDispatcer(this)
}


module.exports = EventDispatcer